Unit 1 • Class 11Environment Science (Grade 11) (Env.413)
Earth as a Closed System & Ecology
बन्द प्रणालीको रूपमा पृथ्वी र पारिस्थितिकी
Earth system spheres (atmosphere, hydrosphere, lithosphere, biosphere), thermodynamic closed system, ecosystem energy flows, K-selected vs r-selected populations.
Lesson Summary & Key Concepts
Thermodynamic nature of Earth as a closed system, interspheric biogeochemical flows, trophic energy transfer via Lindeman 10% law, and comparative population dynamics of r-selected versus K-selected species.
Textbook Exercises & Solutions
Showing 12 of 12 Solved QuestionsQuestion 1• 1 Marks
Question 2• 1 Marks
Question 3• 1 Marks
Question 4• 1 Marks
Question 5• 1 Marks
Question 6• 1 Marks
Question 7• 5 Marks
Question 8• 5 Marks
Question 9• 5 Marks
Question 10• 5 Marks
Question 11• 5 Marks
Question 12• 8 Marks
Quick Revision Takeaways
Common Exam Pitfalls to Avoid
⚠️ Common Error: Confusing open and closed systems when describing Earth.
✓ Correct Approach: Earth is closed to matter, but open to energy.
Why: Sunlight constantly enters and thermal radiation exits into outer space.
Content Provenance & Verification
Editorial Verified & Published
Original Author / ContributorNEB Environmental Science Specialist
Verified BySenior Subject Specialist (TU / NEB Panel)
Curriculum Versionv1.0 (CDC 2078/2080 Grid)
Last Verified Date2026-10-23
Legitimate Official Curriculum References
public curriculum
Found an ambiguity, error, or updated syllabus note?